Most vegetables and fruits have relatively short shelf lives in the ripened condition while flowers do not last long after they are cut. All fresh produce respires after harvest. The largest gas component of this respiration is carbon dioxide. Significantly, ethylene is also generated by botanical respiration which has a catalytic effect on accelerating ripening rate. Ethylene also causes premature death in flowers, even when present in low levels. It is known that shelf life of perishable produce can be lengthened by preserving it in inert gas filled containers. Oxygen, the all-important life giving element, possesses the unfortunate property of supporting the growth of bacteria, which causes food deterioration and discoloration. Improvement in produce shelf life can be gained by reducing the oxygen available for conversion to carbon dioxide, reducing ethylene levels to slow catalytic effects, and maintaining a higher than atmospheric level of carbon dioxide to reduce bacteriological growth. Also, the replacement of oxygen by an inert atmosphere, such as nitrogen, argon or helium inhibits bacterial growth, assuring longer shelf life and retention of flavor and color.
Modified atmosphere containers have been mostly in the form of storage rooms and portable container vans having systems for continuously monitoring and changing the atmosphere to reduce or eliminate oxygen or other gases which affect ripening of produce.
Individual modified atmosphere containers have been tested wherein a sealed container occupied by produce is formed by a high barrier film and filled with a mixture of nitrogen and/or carbon dioxide. One difficulty experienced with such a container is that produce respiration and bacterial action causes gases and volatiles to build up inside the container, resulting in a continuing increase in pressure which eventually produces bulging and even rupture of the container.